Travel safety device for motor vehicle

ABSTRACT

A travel safety device for a vehicle comprises: an object detecting unit ( 114 ) for detecting an object existing in the traveling direction of the vehicle ( 100 ); a correlation calculating unit ( 39 ) for calculating a correlation involving the distance between the vehicle ( 100 ) and the object on the basis of a detection result of the corresponding object detecting unit ( 114 ); an automatic brake unit ( 120 ) for automatically decelerating the vehicle ( 100 ); a safety device ( 122 ) including a seatbelt device ( 15 ) for automatically tightening the seatbelt ( 14 ) and releasing the tightening thereof; and safety device operation control units ( 38, 39, 43 ) for determining a possibility of a contact between the vehicle ( 100 ) and the object on the basis of the correlation calculated by the correlation calculating unit ( 39 ) and for controlling the operation of the safety device ( 122 ) where it is predicted that there is a possibility of a contact; wherein the safety device operation control units ( 38, 39, 43 ) simultaneously actuate the automatic brake unit ( 120 ) and seatbelt device ( 15 ) where it is predicted that there is a possibility of a contact.

TECHNICAL FIELD

The present invention relates to a travel safety device for a vehicle,which improves safety in driving.

BACKGROUND ART

As art pertaining to a travel safety device for a vehicle, whichimproves safety in driving, technology is provided (for example, referto Japanese Patent Publication No. 2946995), in which a seatbelt devicecapable of tightening a seatbelt by means of an electric motor isemployed, and an occupant is restrained in the seat by forciblytightening the seatbelt by means of the electric motor when it ispredicted that a contact between vehicles will occur.

The travel safety device for a vehicle which is disclosed in theabove-described patent document tightens a seatbelt by way of a seatbeltdevice when it is predicted that a contact between vehicles will occur.Since this strictly aims at restraining an occupant in a seat when acontact occurs, the device operates at the moment when the possibilityof a contact between vehicles is increased to a certain degree. Undersuch condition, occupants usually do not recognize that seatbelt isautomatically tightened because the travel safety device just tightensthe seatbelt.

Herein, it is highly desirable that an alarm to warn that there is apossibility of a contact between vehicles be outputted to an occupant atan earlier stage than automatic tightening of a seatbelt to restrain theoccupant. However, the travel safety device described in theabove-described patent document is not provided with a function ofintentionally issuing an alarm to the occupant.

DISCLOSURE OF INVENTION

Therefore, it is an object of the present invention to provide a travelsafety device for a vehicle and a seatbelt device, which are capable ofsuitably issuing an alarm to an occupant.

In order to achieve the above-described object, the present invention isa travel safety device for a vehicle which includes an object detectingunit for detecting an object existing in the traveling direction of thevehicle, a correlation calculating unit for calculating a correlationinvolving the distance between the vehicle and the object on the basisof a detection result of the corresponding object detecting unit, anautomatic brake unit for automatically decelerating the vehicle, asafety unit including a seatbelt device for automatically tightening theseatbelt and releasing the tightening thereof, and a safety deviceoperation control unit for determining a possibility of a contactbetween the vehicle and the object on the basis of the correlationcalculated by the corresponding correlation calculating unit and forcontrolling the operation of the safety device when it is predicted thatthere is a possibility of a contact, wherein the safety device operationcontrol unit simultaneously actuates the automatic brake unit and theseatbelt device where it is predicted that there is a possibility of acontact.

Therefore, if the correlation calculating unit calculates a correlationinvolving the distance between the vehicle and an object existing in itstraveling direction on the basis of a detection result of the objectdetecting unit, in accordance therewith, the safety device operationcontrol unit determines whether or not there is a possibility of acontact between the vehicle and the object. If there is a possibility ofa contact, the safety device operation control unit simultaneouslyactuates the automatic brake unit and the seatbelt device and issues analarm to an occupant. The occupants are caused to recognize that thereis a possibility of a contact between the vehicle and an object. Eventhough when the operation of the automatic brake unit is set out a levelat which an occupant is caused to adequately recognize the possibilityof a contact, the occupant is caused to clearly recognize thepossibility due to actuation of the seatbelt device, and it is possiblefor the occupant to clearly recognize that the automatic brake unit isoperating for prevention of the contact. Therefore, it is possible tourge the occupant to carry out a contact avoiding operation by suitablyissuing an alarm to the occupant.

In the above-described travel safety device for a vehicle, the automaticbrake unit may be constructed so as to be capable of decelerating thevehicle in a plurality of different deceleration patterns. The seatbeltdevice may also be constructed so as to be capable of tightening theseatbelt and releasing the tightening thereof in a plurality ofdifferent operation patterns.

Thus, since it is possible for the automatic brake unit to carry outdeceleration in a plurality of different deceleration patterns andpossible for the seatbelt device to carry out tightening of the seatbeltand releasing the tightening thereof in a plurality of differentoperation patterns, the deceleration and seatbelt actuation may be madedifferent when an alarm is issued to the occupant and when contact withan object is prevented from occurring, and the deceleration andtightening of the seatbelt may be made different in accordance with thedegree of emergency.

In the above-described travel safety device for a vehicle, the safetydevice operation control unit may be constructed so that, when thedistance between the vehicle and an object enters a predetermined rangeon the basis of the correlation calculated by the correlationcalculating unit, the automatic brake unit causes deceleration of adegree, which is capable of making the occupant recognize that a brakingforce has been generated, to be generated, and at the same time, theseatbelt device alternates tightening of the seatbelt and releasingthereof.

Accordingly, as the distance between the vehicle and an object enters apredetermined range, the safety device operation control unit makes theautomatic brake unit generate a degree of deceleration to be recognizedby the occupant that a braking force has been generated, and at the sametime, the seatbelt device alternates tightening of the seatbelt andreleasing thereof. With deceleration of such an automatic brake unit,the occupant is caused to bodily sense a deceleration force, and, inline therewith, is caused to bodily sense fluctuations resulting fromtightening and releasing, which are brought about by the seatbelt of theseatbelt device. Thereby, the occupant is able to securely recognize thedeceleration and seatbelt operation, and therefore an alarm can beissued to cause the occupant to recognize the situation without fail.

In the travel safety device for a vehicle, the safety device operationcontrol unit may be constructed so that deceleration of a higher degreeis generated by the automatic brake unit if such a state is maintainedfor a predetermined period of time, where the distance between thevehicle and an object enters a predetermined range on the basis of thecorrelation calculated by the correlation calculating unit.

Accordingly, when a state where the distance between the vehicle and anobject is within a predetermined range is maintained for a predeterminedperiod of time, that is, when the vehicle is not distanced from theobject even though an alarm has been issued, the safety device operationcontrol unit generates deceleration of a higher degree by the automaticbrake unit. Therefore, should a contact occur, the damage can bereduced.

In the travel safety device for a vehicle, the safety device operationcontrol unit may be constructed so that, if such a state is maintainedfor a predetermined period of time, where the distance between thevehicle and an object enters within a predetermined range on the basisof the correlation calculated by the correlation calculating unit, theseatbelt device causes the seatbelt to be fixed at its stopped state forat least a predetermined period of time after the seatbelt is tightened.

Accordingly, when such a state where the distance between the vehicleand an object enters a predetermined range is maintained for apredetermined period of time, that is, when the vehicle is not distancedfrom an object even though an alarm has been issued, since the safetydevice operation control unit fixes the seatbelt in its stopped statefor at least a predetermined period of time after the seatbelt istightened by the seatbelt device, it is possible to prevent a forwardmovement of an occupant due to an increase in the deceleration degree bythe automatic brake unit. Therefore, it is possible for a driver tocarry out an operation of preventing a contact with an object in afavorable posture.

The above-described travel safety device for a vehicle may be providedwith a braking operation detecting unit for detecting a brakingoperation carried out by a driver and a vehicle speed detecting unit fordetecting the vehicle speed, and the safety device operation controlunit may be constructed so that fixing of the seatbelt in its stoppedstate by the seatbelt device is released at least at one of the stateswhere it is detected, on the basis of a detection result of the brakingoperation detecting unit, that a braking operation is released after thebraking operation is carried out by a driver and where it is detected,on the basis of a detection result of the vehicle speed detecting unit,that the vehicle stops.

Accordingly, if at least any one of the states is detected, where it isdetected on the basis of a detection result of the braking operationdetecting unit that a braking operation is released after the brakingoperation is carried out by a driver and where it is detected on thebasis of a detection result of the vehicle speed detecting unit that thevehicle stops, the safety device operation control unit releases thefixing of the seatbelt in its stopped state by the seatbelt device,therefore, the safety device operation control unit does not need anyreset switch.

The above-described travel safety device of a vehicle may be providedwith a braking operation detecting unit for detecting a brakingoperation carried out by a driver, and the safety device operationcontrol unit may be constructed so that, on the basis of a brakingoperation detected by the braking operation detecting unit, itdetermines whether or not there is a possibility of a contact betweenthe vehicle and an object, and increases a tightening tension of theseatbelt by way of the seatbelt device in the case in which it ispredicted, based on a braking operation carried out by a driver, thatthere is a possibility of a contact, prior to the case in which it ispredicted, on the basis of the correlation between the vehicle and anobject, which is calculated by the correlation calculating unit, thatthere is a possibility of a contact therebetween.

Accordingly, the tightening force of a seatbelt by the seatbelt deviceis increased in the case in which it is predicted on the basis of abraking operation carried out by a driver that there is a possibility ofa contact, that is, where the deceleration degree is suddenly increased,prior to the case in which it is predicted on the basis of the distancebetween the vehicle and an object, which is calculated by thecorrelation calculating unit, that there is a possibility of a contact,wherein it is possible to suddenly prevent the forward motion of anoccupant. Therefore, the driver is able to carry out a contact avoidingoperation with an object in a favorable posture with respect to varioustypes of conditions such as a sudden cutting-in of another vehicle fromthe side.

In the above-described travel safety device for a vehicle, the vehiclemay be provided with an in-vehicle LAN, and the correlation calculatingunit, a brake control unit for controlling the automatic brake unit andan electric seatbelt control unit for controlling the seatbelt devicemay be connected to a connection bus of the in-vehicle LAN.

Accordingly, as the correlation calculating unit calculates thecorrelation involving the distance between the vehicle and an objectexisting in the traveling direction thereof on the basis of a detectionresult of the object detecting unit, the safety device operation controlunit determines, on the basis thereof, whether or not there is apossibility of a contact between the vehicle and the object. When thereis a possibility of a contact, the safety device operation control unitsimultaneously actuates the automatic brake unit and the seatbeltdevice, and issues an alarm to the occupant. Based thereon, it ispossible to cause the occupant to recognize that there is a possibilityof a contact. In addition, if the operation of the automatic brake unitis not at such a level at which the occupant is caused to adequatelyrecognize that there is a possibility of a contact, it is possible tocause the occupant to recognize the possibility of a contact byoperation of the seatbelt device, and it is possible to cause them torecognize that the automatic brake unit is operating to prevent thecontact. Therefore, it is able to urge the driver to carry out a contactavoiding operation by suitably issuing an alarm to the driver.

Since the correlation calculating unit, the brake control unit forcontrolling the automatic brake unit and the electric seatbelt controlunit for controlling the seatbelt device are connected to a connectionbus of the in-vehicle LAN, the electric seatbelt control unit becomesable to control the seatbelt device, for example, on the basis of acontrol signal by the brake control unit, which is outputted based on acalculation result of the correlation calculating unit, wherein it ispossible to easily control mutual timing of the brake operation andseatbelt operation.

The above-described travel safety device for a vehicle may beconstructed so that the operation of the seatbelt device is madedifferent in the case in which there is a possibility of a contact witha stationary object and in the case in which there is a possibility of acontact with a mobile object.

Accordingly, as the correlation calculating unit calculates thecorrelation involving the distance between the vehicle and an objectexisting in the traveling direction thereof on the basis of a detectionresult of the object detecting unit, the safety device operation controlunit determines, on the basis thereof, whether or not there is apossibility of a contact between the vehicle and the object. When thereis a possibility of a contact, the safety device operation control unitsimultaneously actuates the automatic brake unit and the seatbeltdevice, and issues an alarm to the occupant. Based thereon, it ispossible to cause the occupant to recognize that there is a possibilityof a contact. In addition, even though the operation of the automaticbrake unit is not at such a level at which the occupant is caused toadequately recognize that there is a possibility of a contact, it ispossible to cause the occupant to recognize the possibility of a contactby operation of the seatbelt device, and it is possible to cause theoccupant to recognize that the automatic brake unit is operating toprevent the contact. Therefore, it becomes possible to urge the driverto carry out a contact avoiding operation by suitably issuing an alarmto the driver.

Further, since the operation of the seatbelt device is made different inthe case in which there is a possibility of a contact with a stationaryobject and in the case in which there is a possibility of a contact witha mobile object, it is possible to cause the occupant to recognize, byoperation of the seatbelt device, whether the object which may collidewith the vehicle is a stationary object or a mobile object.

The above-described travel safety device for a vehicle may further beprovided with a collision sensor for detecting collision of the vehicle,and the safety device further provided with airbag devices, wherein thesafety device operation control unit may be constructed so that itsimultaneously actuates the automatic brake unit and the seatbelt devicewhen it is predicted that there is a possibility of a contact, andactuates the airbag devices when the contact sensor detects contact ofthe vehicle.

Accordingly, as the correlation calculating unit calculates thecorrelation involving the distance between the vehicle and an objectexisting in the traveling direction thereof on the basis of a detectionresult of the object detecting unit, the safety device operation controlunit determines, on the basis thereof, whether or not there is apossibility of a contact between the vehicle and the object. When thereis a possibility of a contact, the safety device operation control unitsimultaneously actuates the automatic brake unit and the seatbeltdevice, and issues an alarm to the occupant. Based thereon, it ispossible to cause the occupant to recognize that there is a possibilityof a contact. In addition, even though the operation of the automaticbrake unit is not at such a level at which the occupant is caused toadequately recognize that there is a possibility of a contact, it ispossible to cause the occupant to recognize the possibility of a contactby operation of the seatbelt device, and it is possible to cause theoccupant to recognize that the automatic brake unit is operating toprevent the contact. Therefore, it becomes possible to urge the driverto carry out a contact avoiding operation by suitably issuing an alarmto the driver.

Also, since the airbag devices can be actuated due to the collisionsensor's detecting collision of the vehicle after the automatic brakeunit decelerates the vehicle and the seatbelt device tightens theseatbelt, the vehicle is adequately decelerated and the occupant isrestrained when the airbag devices operate, and thus the airbag devicescan be made small.

The present invention also provides a seatbelt device which includes aseatbelt for restraining an occupant of a vehicle in a seat, a contactpredicting unit for predicting a possibility of a contact between thevehicle and an object, an electric motor for tightening the seatbeltwhen a contact is predicted by the contact predicting unit, a tighteningreleasing unit for releasing the tightening of the seatbelt and acontrol unit for controlling the electric motor and the tighteningreleasing unit, wherein the control unit carries out a warning operationto issue an alarm to the occupant by means of the seatbelt bycontrolling the electric motor and the tightening releasing unit so thattightening of the seatbelt and releasing thereof are alternated.

Accordingly, since the control unit controls the electric motor and thetightening releasing unit so that tightening of the seatbelt andreleasing thereof are alternated, a warning operation is carried out, inwhich actuation of the seatbelt in the tightening direction andactuation thereof in the tightening releasing direction can bealternated. Therefore, the occupant is caused to bodily sense theactuation of the seatbelt in the tightening direction and the actuationthereof in the tightening releasing direction. Resultantly, it ispossible to cause the occupant to recognize the same. That is, an alarmis issued to the occupant.

In the seatbelt device, the time of tightening the seatbelt in thewarning operation may be set to be longer than the time of releasing thetightening thereof.

Thus, since the time of tightening the seatbelt in the warning operationis set to be longer than the time of releasing the tightening thereof,the amount of drive in the direction of releasing the tightening afterthe seatbelt is driven in the tightening direction can be reduced. As aresult, it is possible to cause the occupant to bodily sense repetitionof the actuation of the seatbelt in the tightening direction and in thereleasing direction without sensing any incongruity. That is, an alarmcan be issued to the occupant without them sensing any incongruity.

In the seatbelt device, the control unit may be constructed so that thewarning operation is carried out on the basis of a predicting signal ofthe contact predicting unit.

Thus, since the control unit carries out a warning operation based on apredicting signal of the contact predicting unit for predicting apossibility of a contact of the vehicle, it is possible to issue analarm to the occupant when a possibility of a contact of the vehicle ispredicted.

In the seatbelt device, the control unit may be constructed so that,after the warning operation is carried out, a tightening operation oftightening the seatbelt by means of the electric motor is carried out.

Thus, since the control unit carries out a tightening operation oftightening the seatbelt by normally running the electric motor after awarning operation is carried out, the occupant is caused to recognize apossibility of a contact of the vehicle at an earlier stage than atightening operation of the seatbelt, which is carried out when thepossibility of a contact of the vehicle is increased, and are allowed tocarry out a contact avoiding operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general configurational view showing a travel safety deviceof a vehicle according for an embodiment of the invention;

FIG. 2 is a block diagram showing the travel safety device according tothe embodiment of the invention;

FIG. 3 is a general configurational view showing a seatbelt device andits related construction in the travel safety device according to theembodiment of the invention;

FIG. 4 is a linear diagram showing in time-series the current amount ofan electric motor when the seatbelt device in the travel safety deviceaccording to the embodiment of the invention carries out a warningoperation;

FIG. 5 is a linear diagram showing in time-series the tension generatedwhen the seatbelt device in the travel safety device according to theembodiment of the invention carries out a warning operation;

FIG. 6 is a linear diagram showing in time-series the current amounts ofan electric motor when the seatbelt device in the travel safety deviceaccording to the embodiment of the invention predicts a possibility of acontact with a mobile object and predicts a possibility of a contactbased on the brake operation.

FIG. 7 is a linear diagram showing in time-series the current amount ofan electric motor when the seatbelt device in the travel safety deviceaccording to the embodiment of the invention predicts contact with astationary object; and

FIG. 8 is a linear diagram showing in time-series one example ofrespective operation timing of the seatbelt device in the travel safetydevice according to the embodiment of the invention, and decelerationdegrees generated at the respective timing.

BEST MODE FOR CARRYING OUT THE INVENTION

A description is given of a travel safety device for a vehicle accordingto an embodiment of the invention with reference to the drawings.

FIG. 1 depicts a vehicle 100 to which the present embodiment is applied.The vehicle 100 includes left and right front wheels 103, that is, drivewheels to which a drive force of an engine 101 is transmitted via atransmission 102, and left and right rear wheels 104 that are drivenwheels.

In addition, the vehicle 100 includes a brake pedal 106 operated by thedriver, an electronic-controllable negative pressure booster 107 coupledto the brake pedal 106, and a master cylinder 108 coupled to theelectronic-controllable negative pressure booster 107. Herein, theelectronic-controllable negative pressure booster 107 not only actuatesthe master cylinder 108 by mechanically amplifying a depressing force ofthe driver which is applied to the brake pedal 106, but also actuatesthe master cylinder 108 by a signal from a control unit 11 without anoperation of the brake pedal 106. Further, the master cylinder 108generates fluid pressure in response to an output from theelectronic-controllable negative pressure booster 107.

Further, the vehicle 100 includes brake calipers 111 for causing thewheels 103 and 104 to generate a braking force due to the fluid pressureintroduced from the master cylinder 108 and decelerating the vehicle 100and a pressure regulator 112 that is provided between the respectivebrake calipers 111 and the master cylinder 108 and regulates the fluidpressure outputted from the master cylinder 108 while being controlledby the control unit 110.

In addition, the vehicle 100 includes a radar (object detecting unit)114 that is provided at the front part thereof and detects an object,possibly another vehicle, which exists ahead in the traveling directionof the vehicle, by emitting millimeter waves forward and by receivingreflected waves of the millimeter waves from the object, vehicle speedsensors (vehicle speed detecting units) 115 that are provided atpositions corresponding to the respective wheels 103 and 104 and detectthe vehicle speed, etc., based on rotation pulses of the respectivewheels 103 and 104, a brake switch (brake operation detecting unit) 116for detecting an operation of the brake pedal 106 executed by thedriver, a stroke sensor (brake operation detecting unit) 117 fordetecting an operation stroke of the brake pedal 106 executed by thedriver, and a crush sensor (collision sensor) 49 provided at the frontpart to detect collision, a buckle switch 45 for detecting wearing of aseatbelt 14 of a seatbelt device shown in FIG. 3, and a warning lamp 48provided in a meter unit 47 of the instrument panel. These componentsare connected to the control unit 110 as shown in FIG. 2.

Also, an automatic brake unit 120 that automatically decelerates thevehicle 100 by controlling a braking force of the vehicle 100 iscomposed of the electronically-controllable negative pressure booster107, master cylinder 108 and brake calipers 111, which are depicted inFIG. 1. As shown in FIG. 2, a safety device 122 is composed of theautomatic brake unit 120, the seatbelt device 15 for automaticallytightening the seatbelt 14 and releasing the tightening thereof, andairbag devices 121 disposed at respective parts of the vehicle 100.Also, a travel safety device 123 according to the embodiment is composedof the safety device 122, radar 114, vehicle speed sensors 115, brakeswitch 116, stroke sensor 117, crush sensor 49, buckle switch 45,warning lamp 48 and control unit 110.

The control unit 110 calculates a correlation, involving the distancebetween the vehicle and an object ahead in the traveling direction,based on a result of detection by radar 114, specifically, the timing oftransmitting and receiving millimeter waves, and simultaneouslydetermines a possibility of a contact between the vehicle and an objectahead in the traveling direction based on the calculated correlation.When it is predicted that there is a possibility of a contact betweenthe vehicle and an object ahead in the traveling direction, the controlunit 110 controls operation of the safety device 122 composed of theautomatic brake unit 120, seatbelt device 15 and airbag devices 121,which are provided in the vehicle.

The vehicle 100 is provided with seats 13, each of which includes a seatcushion 11 for supporting mainly the buttocks of the occupant 10 and aback rest 12 for supporting the back of the occupant 10 as shown in FIG.3. The seatbelt device 15 that restrains the occupant 10 by usingseatbelt 14 is provided for the seat 13. The seatbelt device 15 is of aso-called three-point type which is provided for the seat 13 of adriver. Also, the seatbelt device 15 is also provided for seats forpassengers other than the driver as a matter of course.

In the seatbelt device 15, webbing 21 of the seatbelt 14 extends upwardfrom a retractor 20 secured to the center pillar (not illustrated) orthe like, at the outer side of the compartment with respect to the seat13, and is inserted in a through anchor 22 supported at the upper partof the center pillar, and simultaneously the tip end of the webbing 21is attached to the vehicle floor side via an outer anchor 23 at theouter side of the compartment with respect to the seat 13. The seatbelt14 includes a tongue plate 25 through which a portion of the webbing 21located between the through anchor 22 and the outer anchor 23 passes.The tongue plate 25 is detachably attached to a buckle 26 attached tothe vehicle floor side inside the compartment with respect to the seat13.

The occupant 10 seated in the seat 13 pull out the seatbelt 14 from theretractor 20 by pulling the tongue plate 25 and attaches the tongueplate 25 into the buckle 26, wherein a portion of the seatbelt 14 fromthe through anchor 22 to the tongue plate 25 draws mainly the portionfrom the shoulder to the breast of the occupant 10 into the seat 13 atthe opposite side thereof, and a portion from the tongue plate 25 to theouter anchor 23 draws mainly the abdomen of the occupant 10 into theseat 13 at the opposite side thereof.

The retractor 20 is provided with an irreversible first pretensioner(irreversible seatbelt tightening unit) 28 that instantaneously retractsthe seatbelt 14 with an explosive force using explosive powder. Thefirst pretensioner 28 may be of an explosive type, a spring type, etc.

In addition, the retractor 20 is provided with a reversible secondpretensioner 30 that tightens the seatbelt 14 by retracting the seatbelt14 by the drive force of an electric motor 29. That is, the secondpretensioner 30 is constructed so that it sends out the seatbelt 14 inthe releasing direction by forcibly reversing a reel 31 in line withreversing of the electric motor 29 while it retracts the seatbelt 14 byforcibly turning the reel 31 for winding the webbing 21 into theretractor 20 in line with turning of the electric motor 29.

An electrical seatbelt control unit (safety device operation controlunit) 35 which is a part of the control unit 110 for controlling thedrive of the electric motor 29 is connected to the electric motor 29.The electrical seatbelt control unit 35 eliminates a slack of theseatbelt 14 in advance when a contact with a object ahead of the vehicleis predicted and restrains the occupant 10, and the electrical seatbeltcontrol unit 35 also controls the electric motor 29 so as toautomatically wind the seatbelt 14 into the retractor 20 when wearing ofthe seatbelt is ended. The electrical seatbelt control unit 35 isconnected to a connection bus 36 of the in-vehicle LAN.

A brake control unit (safety device operation control unit) 38 that is acontrol unit for controlling a vehicle behavior stabilization controlsystem to control behavior stabilization of the vehicle and is a part ofthe control unit 110, a radar control unit (correlation calculatingunit, safety device operation control unit) 39 that is a control unitfor controlling a preceding vehicle tracking control system to cause thevehicle to run while tracking the preceding vehicle and is a part of thecontrol unit 110, and a vehicle speed measuring unit 40 that is a partof the control unit 110 are connected to the connection bus 36.

Also, an airbag control unit (safety device operation control unit) 43that is a part of the control unit 110 and controls the operation of theairbag device 121 which is a seatbelt auxiliary tightening unit isconnected to the electrical seatbelt control unit 35.

The brake control unit 38 carries out brake assistance control by, forexample, predicting that a contact with an object ahead of the vehicleis possible if the brake control unit 38 detects an imminent brakeoperation based on output of the stroke sensor 117, which is a brakeoperation speed sensor, when the speed at which the brake pedal 106 ispressed is faster than a predetermined speed, wherein a BA signal isoutputted to the electrical seatbelt control unit 35 during execution ofthe brake assistance control. In addition, the brake control unit 38predicts that there is no possibility of a contact when the speed atwhich the brake pedal 106 is not pressed faster than the predeterminedspeed. In this case, no BA signal is outputted.

The preceding vehicle tracking control system includes the radar 114such as a millimeter wave radar, which detects an object ahead in thetraveling direction of the vehicle, (for example, a preceding vehicle).The radar 114 detects an object ahead, and on the basis of a detectionsignal of the radar 114, the radar control unit 39 controls theelectronically-controllable negative pressure booster 107 that is abrake fluid pressure control unit of the automatic brake unit 120, andfurther controls the braking force of the vehicle 100. The radar controlunit 39 also controls acceleration and deceleration by controlling athrottle actuator (not illustrated), and controls preceding vehicletracking while keeping a predetermined distance between the precedingvehicle and the following vehicle. And further, the radar 114 detects anobject ahead, and if the distance between the vehicle and the objectahead enters a predetermined range, the radar control unit 39 predictsthat a contact of the vehicle 100 is possible based on the detectionsignal of the radar 114, and the radar control unit 39 carries outautomatic brake control, which contributes to reducing damage due to acontact with an object ahead by controlling theelectronically-controllable negative pressure booster 107, which is abrake fluid pressure control unit of the automatic brake unit 120, andby generating a braking force. Also, on the basis of a detection signalof the radar 114, unless the distance between the object ahead and thevehicle is within the predetermined range, the radar control unit 39predicts that there is no possibility of a contact of the vehicle.

Herein, for example, if the object ahead is detected by the radar 114and, on the basis of a detection signal of the radar 114, the distanceto the object ahead is reduced to a predetermined range or less, theradar control unit 39 predicts that a contact between the object aheadand the vehicle 100 is possible, and carries out automatic brakecontrol. Further, it is determined, on the basis of a difference in therelative speed between the object and the vehicle 100, whether theobject is a stationary object or a mobile object. That is, the radarcontrol unit 39 predicts a possibility of a contact with a stationaryobject ahead in the traveling direction of the vehicle and also predictsa possibility of a contact with a mobile object ahead in the travelingdirection of the vehicle.

And, in the automatic brake control, if the radar control unit 39determines that the object for which there is a possibility of a contactis a stationary object, the radar control unit 39 outputs, duringexecution of automatic brake control, a stationary object signal, whichis a prediction signal showing that the vehicle is in a state where itis predicted that there is a possibility of a contact with thestationary object, to the electrical seatbelt control unit 35. On theother hand, if the radar control unit 39 determines that the object forwhich there is a possibility of a contact is a mobile object, the radarcontrol unit 39 outputs, during execution of automatic brake control, amobile object signal, which is a prediction signal showing that thevehicle is in a state where it is predicted that there is a possibilityof a contact with the mobile object, to the electrical seatbelt controlunit 35. In addition, unless under execution of automatic brake control,the radar control unit 39 does not output the stationary object signalor the mobile object signal.

Also, a vehicle speed signal from the vehicle speed sensor 115 isoutputted from the vehicle speed measuring unit 40 to the electricalseatbelt control unit 35, and when the brake switch 116 is turned on, abrake signal is outputted to the electrical seatbelt control unit 35.

A buckle switch 45 for detecting whether or not the tongue plate 25 ofthe seatbelt 14 of the seatbelt device 15 is engaged with the buckle 26,that is, whether or not the seatbelt 14 is being worn is connected tothe airbag control unit 43. Further, a warning lamp 48 secured in themeter unit 47 of the instrument panel is connected to the airbag controlunit 43. In addition, a crush sensor 49 for detecting collision of thevehicle is connected to the airbag control unit 43.

And, the airbag control unit 43 controls operation of the respectiveairbag devices 121 and an explosive powder type first pretensioner 28,etc., on the basis of a buckle signal which is outputted from the buckleswitch 45 when the tongue plate 25 is engaged with the buckle 26 andwhose outputting from the buckle switch 45 is stopped when the tongueplate 25 is disengaged from the buckle 26, and a detection signal of thecrush sensor 49.

As shown in FIG. 4, the electrical seatbelt control unit 35 of theseatbelt device 15 according to the embodiment drives the electric motor29 of the second pretensioner 30 so that the electric motor 29 repeatsturning in the direction of tightening the seatbelt 14 and reversing inthe direction of releasing the tightening of the seatbelt 14 alternatelya predetermined number of times (specifically, three times) for apredetermined period of time, wherein a warning operation which issuesan alarm to the occupant 10 is carried out by the seatbelt 14.

In detail, for the first time of turning and reversing in the warningoperation, the drive time (from to t01 to t02 in FIG. 4) of turning ofthe electric motor 29 is set to a predetermined first turning drive time(for example, 100 ms), and the drive time (from t03 to t04 in FIG. 4) ofreversing of the electric motor 29 is set to a predetermined firstreversing time (for example, 50 ms), wherein the first turning drivetime is set to be longer than the first reversing drive time. Also, thepause time (from t02 to t03 in FIG. 4) between turning and reversing isset to be a short predetermined first pause time (for example, 10 ms).

For the second time of turning and reversing, which are carried out witha pause time (for example, 150 ms) with respect to the first time ofturning and reversing, the drive time (from t05 to t06 in FIG. 4) ofturning of the electric motor 29 is set to a predetermined secondturning drive time (for example, 100 ms), and the drive time (from t07to t08 in FIG. 4) of reversing of the electric motor 29 is set to apredetermined second reversing drive time (for example, 50 ms), whereinthe second turning drive time is set to be longer than the secondreversing drive time. Also, the pause time (from t06 to t07 in FIG. 4)between turning and reversing is set to be a short predetermined secondpause time (for example, 10 ms). That is, for the second time of turningand reversing, the turning drive time, the reversing drive time and thepause time between turning and reversing are set to the same lengths asthose in the first time of turning and reversing.

For the third time of turning and reversing, which are carried out witha pause time (for example, 150 ms) with respect to the second time ofturning and reversing, the drive time (from t09 to t10 in FIG. 4) ofturning of the electric motor 29 is set to a predetermined third turningdrive time (for example, 100 ms), and the drive time (from t11 to t12 inFIG. 4) of reversing of the electric motor 29 is set to a predeterminedthird reversing drive time (for example, 100 ms), wherein the thirdturning drive time and the third reversing drive time are set to thesame duration of time. Also, the pause time (from t10 to t11 in FIG. 4)between turning and reversing is set to be a long predetermined thirdpause time (for example, 50 ms). That is, in the third time of turningand reversing, the turning drive time and reversing drive time of theelectric motor 29 are set to the same duration of time as the first andsecond turning drive times, and the pause time between turning andreversing are set to be longer than the first time and second pausetimes.

Also, in the first time through the third time, the drive current forturning is controlled so as to become a predetermined first drive amount(for example, 3 A), and the drive current for reversing is controlled soas to become a predetermined second drive amount (for example, 7 A inthe inverted direction). Herein, in FIG. 4, the broken lines indicatecontrol targets of current values while the solid lines indicate actualoperation current values.

By such a warning operation, as shown in FIG. 5, generation of tensionby winding the seatbelt 14, that is, driving the same in the tighteningdirection, and releasing of tension by unwinding the seatbelt 14, thatis, driving the same in the releasing direction are repeated a pluralityof times within a predetermined duration of time, whereby an alarm isissued to the occupant 10 by means of the seatbelt 14.

And, the electrical seatbelt control unit 35 of the seatbelt device 15controls the electric motor 29 in accordance with a predicting result ofthe brake control unit 38 and radar control unit 39, which predict apossibility of a contact of the vehicle, and carries out a tighteningoperation to generate tension of the seatbelt 14. Also, the electricalseatbelt control unit 35 carries out a tightening operation at theearliest timing of determination among a predicting determination timingwhen the radar control unit 39 predicts a possibility of a contact witha stationary object ahead in the traveling direction of the vehicle(that is, at the moment when a stationary object signal is generated), apredicting determination timing when the radar control unit 39 predictsa possibility of a contact with a mobile object ahead in the travelingdirection of the vehicle (that is, at the moment when a mobile objectsignal is generated), and a predicting determination timing when thebrake control unit 38 determines that a possibility of a contact ispredicted based on an operation speed of the brake pedal (that is, atthe moment when a BA signal is generated).

Further, the electrical seatbelt control unit 35 causes the seatbelt 14to generate different amount of tension in accordance with a result ofpredicting a possibility of a contact by the brake control unit 38 orresults of predicting a possibility of a contact by the radar controlunit 39. In detail, the electric motor 29 is controlled so that tensionF2, generated by the electric motor 29 when the radar control unit 39predicts a possibility of a contact with a mobile object ahead in thetraveling direction of the vehicle, and tension F1, generated by theelectric motor 29 when the brake control unit 38 predicts a possibilityof a contact based on the operation speed of the brake pedal 106 becomegreater than tension F3, generated by the electric motor 29 when theradar control unit 39 predicts a possibility of a contact with astationery object ahead in the traveling direction of the vehicle.

For example, when the possibility of a contact is predicted based on thebrake operation, the current value of the electric motor 29 iscontrolled so as to be brought into the first predetermined range (forexample, 10 A through 20 A) in order to cause the first predeterminedvalue of tension (for example, 100 N) as the tension F1 to be generatedfor the seatbelt 14. Also, when the possibility of a contact with amobile object is predicted, the current value of the electric motor 29is controlled so as to be brought into the second predetermined range(for example, 10 A through 20 A) in order to cause the secondpredetermined value of tension (for example, 100 N) as the tension F2 tobe generated for the seatbelt 14. Further, when the possibility of acontact with a stationary object is predicted, the current value of theelectric motor 29 is controlled so as to be brought into the thirdpredetermined range (for example, 6 A through 10 A) in order to causethe third predetermined value of tension (for example, 50 N) as thetension F3 to be generated for the seatbelt 14. In the example, thefirst predetermined value representing the tension F1 and the secondpredetermined value representing the tension F2 are set to be the same.As a result, the first predetermined range of the current value is setto be equal to the second predetermined range of the current value.

In addition, in restraining operations in the case in which apossibility of a contact with a stationary object is predicted, apossibility of a contact with a mobile object is predicted, or apossibility of a contact is predicted based on the brake operation, theelectrical seatbelt control unit 35 temporarily increases the currentvalue of the electric motor 29 at the beginning when the seatbelt 14 iscaused to generate tension by which the occupant 10 is secured orrestrained, by controlling the electric motor 29. That is, within apredetermined duration of time immediately after rotation of theelectric motor 29 is started, the current limit is made higher than thecurrent limit required when generating the tension established by arestraining operation.

Specifically, when the possibility of a contact is predicted based onthe brake operation, shown in FIG. 6 as from t21 to t22, the currentlimit is set at the first initial limit value (for example, 20 A) for apredetermined first initial time (for example, 50 ms) immediately afterrotation of the electric motor 29 is started, and thereafter, thecurrent limit is set to a predetermined first limit value (for example,10 A) which is lower than the first initial limit value. Also, when thepossibility of a contact with a mobile object is predicted, shown inFIG. 6 as from t21 to t22, the current limit is set at a predeterminedsecond initial limit value (for example, 20 A) for a predeterminedsecond initial time (for example, 50 ms) immediately after rotation ofthe electric motor 29 is started, and thereafter, the current limit isset to a predetermined second limit value (for example, 10 A) which islower than the second initial limit value. Further, when the possibilityof a contact with a stationary object is predicted, shown in FIG. 7 asfrom t31 to t32, the current limit is set at a predetermined thirdinitial limit value (for example, 10 A) for a predetermined thirdinitial time (for example, 50 ms) immediately after rotation of theelectric motor 29 is started, and thereafter, the current limit is setto a predetermined third limit value (for example, 6 A) which is lowerthan the third initial limit value. In the example, since the firstpredetermined value representing the tension F1 is equal to the secondpredetermined value representing the tension F2, the first initial limitvalue and the second initial limit value are set to be equal to eachother, and at the same time, the first limit value and the second limitvalue are also set to be equal to each other. Herein, in FIG. 6 and FIG.7, the broken lines indicate control targets of the current values, andthe solid lines indicate actual operation current values.

Also, the electric motor 29 may be controlled so that the tension F2when predicting a possibility of a contact with a mobile object is madegreater than the tension F3 when predicting a possibility of a contactwith a stationary object, and simultaneously the tension F1 whenpredicting a possibility of a contact based on the brake operation ismade greater than the tension F2 when predicting a possibility of acontact with a mobile object (That is, F3<F2<F1).

That is, the electrical seatbelt control unit 35 determines apossibility of a contact between the vehicle 100 and an object based onan operation of the brake pedal 106, which is detected by a strokesensor 117 and outputted by the brake control unit 38, and if apossibility of a contact is predicted based on a brake operation of thedriver, the electrical seatbelt control unit 35 increases therestraining tension of the seatbelt 14 made by the seatbelt device 15even though a possibility of a contact is also predicted based on thedistance between the vehicle 100 and an object which is calculated bythe radar control unit 39.

In this case, for example, the third predetermined range of the currentvalue of the electric motor 29 is controlled so as to become, forexample, 6 A through 10 A when the possibility of a contact with astationary object is predicted, and at the same time, the secondpredetermined range of the current value of the electric motor 29 iscontrolled so as to become, for example, 10 A through 20 A when thepossibility of a contact with a mobile object is predicted. Also, thefirst predetermined range of the current value of the electric motor 29is controlled so as to become, for example, 20 A through 25 A when thepossibility of a contact is predicted based on the brake operation. Inthis case, the first initial limit value is set higher than the secondinitial limit value, and the first limit value is set higher than thesecond limit value.

Hereinafter, a description is given, in time series, of one example ofrespective operations of the travel safety device 123 according to theembodiment along with generation states of deceleration degrees withreference to FIG. 8.

In the case in which the radar 114 detects an object ahead (for example,a vehicle existing ahead) and that the distance to the forward object isreduced to a predetermined value or less, the radar control unit 39commences automatic brake control (t41 in FIG. 8) based on a detectionsignal of the radar 114, and outputs a stationary object signal when theforward object is a stationary object, or a mobile object signal whenthe forward object is a mobile object, and in the initial stage (fromt41 to t42 in FIG. 8) the occupant is notified of the distance to theforward object being reduced, by means of sound by an alarm buzzer orthe like, by driving a sound output unit and display by lighting of thewarning lamp 48 (primary warning) or the like. That is, when there is apossibility of a contact with a forward object or when the distancebetween vehicles has shortened, the occupant is notified of the same bymeans of sound and visual display, thereby urging the driver to carryout an avoiding operation. At this time, no deceleration is executed.

Next, if the state where the distance to the object ahead is reduced toa predetermined value or less is maintained for a predetermined durationof time (for example, 1 second) even though a sound output is issued,the radar control unit 39 controls the electronically-controllablenegative pressure booster 107 that is a brake fluid pressure controlunit, and generates a braking force so that the vehicle obtains apredetermined degree of deceleration, whereby the first stage of adeceleration generating operation is carried out, by which the occupantis caused to bodily sense through the deceleration that the brakingforce is being generated (from t42 to t43 in FIG. 8).

Further, if the state where the distance to the object ahead is reducedto a predetermined value or less is maintained for a predeterminedduration of time (for example, 0.5 seconds) even after generation of thedeceleration, the radar control unit 39 controls theelectronically-controllable negative pressure booster 107 that is thebrake fluid pressure control unit of the automatic brake unit 120 andgenerates a braking force so that the vehicle obtains a further higherdegree of deceleration, whereby the second stage of decelerationgeneration is carried out, by which the occupant is notified ofgeneration of the braking force (from t43 to t44 in FIG. 8).

On the other hand, in a state where automatic brake control is beingcarried out in a state where the radar control unit 39 predicts thatthere is a possibility of a contact with a mobile object ahead of thevehicle, the electrical seatbelt control unit 35 receives a mobileobject signal. If the mobile object signal continues to be inputted tothe electrical seatbelt control unit 35 for the predetermined time whichis the same length of time as to generate the braking force (forexample, 1 second) in the above-mentioned condition (t42 in FIG. 8), theelectrical seatbelt control unit 35 carries out a warning operationusing the seatbelt 14 to issue an alarm to the occupant on the basis ofthe mobile object signal, by driving the electric motor 29 of the secondpretensioner 30 so that turning in the direction of tightening theseatbelt 14 and reversing in the direction of releasing the tighteningof the seatbelt 14 are alternated a plurality of times under thecondition that a buckle signal is outputted from the buckle switch 45 isinputted to the electrical seatbelt control unit 35 via the airbagcontrol unit 43.

As shown in FIG. 4, the warning operation is brought about by turningthe electric motor 29 for a predetermined first turning drive time (forexample, 100 ms), stopping it for a predetermined first pause time (forexample, 10 ms), reversing it for a predetermined first reversing drivetime (for example, 50 ms) and stopping it for a predetermined pause time(for example, 150 ms), turning the electric motor 29 for a predeterminedsecond turning drive time (for example, 100 ms), stopping it for apredetermined second pause time (for example, 10 ms), reversing it for apredetermined second reversing drive time (for example, 50 ms), stoppingit for a predetermined pause time (for example, 150 ms), turning theelectric motor 29 for a predetermined third turning drive time (forexample, 100 ms), stopping it for a predetermined third pause time (forexample, 50 ms), and reversing it for a predetermined third reversingdrive time (for example, 100 ms).

Based on the above-described warning operation, as shown in FIG. 5, thegeneration of tension by winding the seatbelt 14, that is, tighteningthereof, and the releasing of the tension by unwinding the seatbelt 14,that is, releasing of the tightening are alternated, wherein an alarm isissued to the occupant via the seatbelt 14. Also, the warning operationis established so as to be carried out almost simultaneously with theabove-described deceleration generation (t42 through t44 in FIG. 8).Herein, along with the warning operation, visual warning by means of thewarning lamp 48, etc., acoustic warning by means of a sound output unit,and other warnings by means of still another warning units may beavailable, or any combination of these warning units may be possible.

That is, if a state where the distance between the vehicle 100 and anobject is within a predetermined range based on the calculatedcorrelation is maintained for a predetermined duration of time eventhough the primary warning is generated, it is determined that thevehicle approaches the object more than when the primary warning isgenerated, and the radar control unit 39 causes the automatic brake unit120 to execute light braking and to generate deceleration of a degree,by which the occupant can be notified of generation of a braking force,in addition to a sound by an alarm buzzer or the like, and display bylighting of the warning lamp 48 or the like, and at the same time, theelectronic seatbelt controlling unit causes the seatbelt device 15 torepeatedly execute light tightening of the seatbelt 14 and release thetightening thereof alternately (secondary warning). That is, when thevehicle approaches the object more than when the primary warning isgenerated, the occupant is notified of the approach by the degree ofdeceleration and tightening of the seatbelt 14 in addition to the soundand visual display, thereby urging the driver to carry out an avoidingoperation.

As described above, where it is predicted on the basis of the calculatedcorrelation that there is a possibility of a contact between the vehicle100 and an object, the radar control unit 39 and the electrical seatbeltcontrol unit 35 simultaneously actuate the automatic brake unit 120 andthe seatbelt device 15.

If a state where the distance between the vehicle and an object ahead isreduced to a predetermined amount or less is maintained for apredetermined duration of time (for example, 2 seconds) even though thesecondary warning in which the deceleration generation operation andwarning operation are added is carried out, the radar control unit 39controls the electronically-controllable negative pressure booster 107that is the brake fluid pressure control unit and carries out anautomatic emergency brake operation (after t44 in FIG. 8) by which abraking force is generated so that the vehicle is able to obtain afurther higher predetermined degree of deceleration.

That is, the radar control unit 39 generates a further higher degree ofdeceleration by the automatic brake unit 120 based on the calculatedcorrelation if a state where the distance between the vehicle 100 and anobject enters a predetermined range is maintained for a predeterminedduration of time.

On the other hand, when the radar control unit 39 predicts that there isa possibility of a contact with an object ahead of the vehicle andoutputs a stationary object signal or a mobile object signal to theelectric seatbelt control unit 35 during execution of automatic brakecontrol, if the electric seatbelt control unit 35 determines based onthe inputted signal that the same predetermined time (for example, 2seconds) as that for determining commencement of the automatic emergencybrake operation in a state where an input of the signal maintainselapses (t44 in FIG. 8), the electric seatbelt control unit 35 carriesout winding and tightening of the seatbelt 14 by turning the electricmotor 29 for a predetermined turning duration of time (for example, 1second), after that, the electric seatbelt control unit 35 carries out arestraining operation for fixing (that is, releasing is made impossible)the retractor 20 at least for a predetermined duration of time (forexample, 2 seconds) by means of the electric motor 29, therebyrestraining the occupant 10 in the seat 13 by means of the seatbelt 14.

That is, if a state where the distance between the vehicle 100 and anobject enters within a predetermined range based on the correlationcalculated by the radar control unit 39 is maintained for apredetermined duration of time, the electrical seatbelt control unit 35fixes the seatbelt 14 in a stopped state for at least a predeterminedduration of time after tightening the seatbelt 14 by means of theseatbelt device 15.

Herein, where a stationary object signal is outputted in the restrainingoperation, that is, when it is predicted that there is a possibility ofa contact with a stationary object ahead of the vehicle, the currentvalue is temporarily increased by setting the current limit to apredetermined third initial limit value (for example, 10 A) for apredetermined third initial time (for example, 50 ms) immediately afterrotation of the electric motor 29 is commenced, and slack of theseatbelt 14 is immediately removed. On the other hand, the current limitthereafter is set to a predetermined third limit value (for example, 6A) which is lower than the third initial limit value to lower thecurrent value, and the tension of the third predetermined value (forexample, 50 N) is generated for the seatbelt 14 as the tension F3. Also,where a mobile object signal is outputted in the restraining operation,that is, when it is predicted that there is a possibility of a contactwith a mobile object (a preceding vehicle) ahead of the vehicle, thecurrent value is temporarily increased by setting the current limit to apredetermined second initial limit value (for example, 20 A) for apredetermined second initial time (for example, 50 ms) immediately afterrotation of the electric motor 29 is commenced, and slack of theseatbelt 14 is immediately removed. On the other hand, the current valuethereafter is set to a predetermined second limit value (for example, 10A) which is lower than the second initial limit value to lower thecurrent value, and the tension of the second predetermined value (forexample, 100 N) is generated for the seatbelt 14 as the tension F2.

That is, if a state where the distance between the vehicle 100 and anobject enters a predetermined range on the basis of the calculatedcorrelation is maintained for a predetermined duration of time eventhough the above-described secondary warning is issued, it is determinedthat the vehicle approaches an object ahead more than at the time of thesecondary warning and that it is difficult to avoid a contact with theobject, the radar control unit 39 carries out intensive braking by theautomatic brake unit 120 in addition to activating a sound such as analarm buzzer and display such as lighting of the warning lamp 48, and atthe same time, the electric seatbelt control unit carries out intensivetightening of the seatbelt 14 by means of the seatbelt device 15. Thatis, where the vehicle approaches the object more than at the time of thesecondary warning, sound and visual display are brought about, andsimultaneously a greater degree of deceleration is generated, and damagefrom any contact is limited. Furthermore, forward movement of theoccupant due to an increase in the degree of deceleration brought aboutby the automatic brake unit 120 can be prevented by intensiverestraining of the seatbelt 14. Simultaneously, a driver restrainingeffect can be increased by an irreversible first pretensioner 28described later.

After that, in the case in which an operation of the brake pedal 106 iscancelled and a brake signal from the brake switch 116 is stopped, or itis determined based on an output of the vehicle speed sensor 115 thatthe vehicle speed becomes zero after a brake operation is carried out bythe driver and a brake signal is outputted from the brake switch 116(t45 in FIG. 8), the electric seatbelt control unit 35 releases fixingof the retractor 20 in a stopped state via the electric motor 29, thatis, ends the restraining operation.

That is, in at least at one of the states where it is detected on thebasis of a detection result of the brake switch 116 that a brakeoperation is cancelled after the brake operation is carried out by thedriver, and where it is detected on the basis of a detection result ofthe vehicle speed sensor 115 that the vehicle 100 stops, the electricalseatbelt control unit 35 ends fixing of the seatbelt 14 in a stoppedstate by the seatbelt device 15. In addition, the broken line in FIG. 8indicates a deceleration segment produced by the brake operation carriedout by the driver.

Also while traveling, it is determined on the basis of output of thestroke sensor 117, which is a brake operation speed sensor, that thespeed at which the brake pedal 106 is stepped on is faster than apredetermined speed and the brake operation is imminent, the brakecontrol unit 38 predicts that there is a possibility of a contact withan object ahead of the vehicle and carries out brake assistance control.As a result, the degree of deceleration is instantaneously increased(that is, as shown by a two-dashed broken line in FIG. 8). The electricseatbelt control unit 35 carries out the above-described tighteningoperation during execution of the brake assistance control, prior to thetightening operation based on the correlation calculated by the radarcontrol unit 39, thereby restraining the occupant 10 in the seat 13 bymeans of the seatbelt 14.

Further, if the crush sensor 49 detects a collision of the vehicle, theairbag control unit 43 inflates the airbag devices 121, and at the sametime, ignites an explosive type first pretensioner 28 to cause theseatbelt 14 to be instantaneously retracted to tighten the same.

That is, the airbag control unit 43 controls the operations of theairbag devices 121 and the irreversible first pretensioner 28 when thecrush sensor 49 detects a collision of the vehicle.

As described above, the automatic brake unit 120 is capable ofdecelerating the vehicle in accordance with a plurality of differentdeceleration patterns, and the seatbelt 15 is capable of tightening theseatbelt 14 and releasing the tightening thereof in accordance with aplurality of different operation patterns. In addition, the automaticbrake unit 120 is provided with a switch by which the driver can turnoff the travel safety device 123 by a manual operation.

With the travel safety device 123 for a vehicle according to theembodiment described above, when the radar control unit 39 calculatesthe correlation including the distance between the vehicle 100 and anobject existing in the traveling direction on the basis of a detectionresult of the radar 114, it is determined that there is a possibility ofa contact between the vehicle 100 and the object on the basis of thecorrelation. When there is a possibility of a contact, the radar controlunit 39 automatically decelerates the vehicle 100 by the automatic brakeunit 120 which is a safety device 122 secured in the vehicle 100, andsimultaneously carries out tightening of the seatbelt 14 and releasingthe tightening thereof by the seatbelt device 15 in line therewith. Theoccupant is caused to bodily sense the deceleration force bydeceleration brought about by such an automatic brake unit 120, and theoccupant is also caused to bodily sense shaking by the seatbelt 14 basedon tightening of the seatbelt 14 by the seatbelt device 15 and releasingof the tightening thereof, which are carried out in line with thedeceleration. That is, an alarm is issued to the occupant. Therefore, itis made possible for the driver to carry out a contact avoidingoperation by suitably issuing an alarm to him. Accordingly, it ispossible for the occupant in the front passenger's seat, etc., toprepare a posture against a contact. In addition, even if the operationof the automatic brake unit 120 is not at such a level at which it ispossible to cause the occupant to adequately recognize that there is apossibility of a contact, the occupant can be caused to recognize thesame by operation of the seatbelt device 15, and it is possible to causethe occupant to clearly recognize that the automatic brake unit 120 isoperating for avoidance of the contact.

Also, since the automatic brake unit 120 is capable of decelerating thevehicle 100 in a plurality of different patterns and the seatbelt device15 is capable of tightening the seatbelt 14 and releasing the tighteningthereof in a plurality of different operation patterns, the degree ofdeceleration and the operations of the seatbelt 14 can be made differentwhen an alarm is issued to the driver and when an avoiding operation iscarried out. Further, it is possible to make the deceleration of thevehicle 100 and operation of the seatbelt 14 different in accordancewith the degree of emergency.

Still further, when the distance between the vehicle 100 and an objectenters a predetermined range, the radar control unit 39 generates, bythe automatic brake unit 120, a deceleration of a degree by which theoccupant is caused to recognize that a braking force is generated, andat the same time, the electronic seatbelt control unit alternatestightening of the seatbelt 14 and releasing of the tightening thereof bythe seatbelt device 15, and it is possible for the occupant to securelyrecognize the same. Therefore, an alarm is issued so that the occupantcan recognize the same without fail.

In addition, when a state where the distance between the vehicle 100 andan object enters a predetermined range is maintained for a predeterminedduration of time, that is, when the distance between the vehicle and anobject is not increased even though an alarm is issued, the radarcontrol unit 39 generates a further higher degree of deceleration bymeans of the automatic brake unit 120. Therefore, should any contactoccur, damage can be reduced.

Further, when a state where the distance between the vehicle 100 and anobject enters a predetermined range is maintained for a predeterminedduration of time, that is, where the distance between the vehicle 100and an object is not increased even though an alarm is issued, theelectrical seatbelt control unit 35 fixes the seatbelt 14 in a stoppedstate for at least a predetermined duration of time after it tightensthe seatbelt 14 by the seatbelt device 15. Therefore, it is possible toprevent the occupant from moving forward in line with an increase in thedeceleration degree by the automatic brake unit 120. Accordingly, it ispossible for the driver to carry out a contact avoiding operation withan object in a favorable posture.

In addition, if one of the states is detected where it is detected onthe basis of a detection result of the brake switch 116 that a brakeoperation is ended after the brake operation is carried out by thedriver and where it is detected on the basis of a detection result ofthe vehicle speed sensor 115 that the vehicle 100 stops, the electricalseatbelt control unit 35 ends fixing of the seatbelt 14 in a stoppedstate by the seatbelt device 15, and no reset switch is required.

Also, when it is determined on the basis of a brake operation of thedriver in accordance with a detection result of the stroke sensor 117that there is a possibility of a contact, that is, where the degree ofdeceleration is suddenly increased, the tightening tension of theseatbelt 14 by the seatbelt device 15 is increased prior to the case inwhich it is determined on the basis of the distance between the vehicle100 and an object, which is calculated by the radar control unit 39,that there is a possibility of a contact. Therefore, it is possible toimmediately prevent forward movement of the occupant. Accordingly, withregard to various patterns such as a sudden cutting-in of anothervehicle from the side, the occupant 10 can carry out a contact avoidingoperation with an object in a favorable posture.

In addition, where the crush sensor 49 detects a contact of the vehicle100, it is possible to actuate the airbag devices 121 and the firstpretensioner 28 for carrying out irreversible tightening of the seatbeltby means of the airbag control unit 43. Therefore, the occupant can berestrained in the seat 13 by the first pretensioner 28 without fail whenthe vehicle 100 collides, and the airbag devices 121 can be operated,and damage due to the contact can be reduced.

Further, since the first pretensioner 28 can be actuated afterdeceleration is carried out by the automatic brake unit 120, the firstpretensioner 28 can be made small-sized. Further, it is possible tooperate the airbag unit 121 and the first pretensioner 28 at the sametime by detection of a collision of the vehicle by means of the crushsensor 49.

Also, since it is possible to actuate the airbag devices 121 based ondetection of a collision of the vehicle by means of the crush sensor 49after the automatic brake unit 120 decelerates the vehicle speed and theseatbelt 14 is tightened by the seatbelt device 15, the vehicle can besufficiently decelerated when the airbag devices 121 operate and thedriver is restrained, and the airbag devices 121 can be made small insize.

In addition, since the radar control unit 39, brake control unit 38, andelectrical seatbelt control unit 35 are connected to the connection bus36 of the in-vehicle LAN, respective timing of the brake operation andseatbelt operation can be controlled easily. For example, the electricalseatbelt control unit 35 becomes able to control the seatbelt device 15on the basis of a BA signal of the brake control unit 38, which isoutputted based on a calculation result of the radar control unit 39.

Further, since the operations of the seatbelt device 15 are madedifferent where there is a possibility of a contact with a stationaryobject and where there is a possibility of a contact with a mobileobject, it is possible to cause the occupant to recognize, by theoperations of the seatbelt device 15, whether the object that is broughtinto contact with the vehicle is a stationary object or a mobile object.

Also, the seatbelt device 15 brings about the following effects.

Since the electrical seatbelt control unit 35 drives the electric motor29 so as to alternate turning and reversing, such warning operation canbe executed, in which drive of the seatbelt 14 in the tighteningdirection and drive in the releasing direction of the tightening arealternated. Therefore, the occupant 10 is caused to bodily sense drivein the tightening direction of the seatbelt 14 and drive in thereleasing direction thereof. As a result, the occupant 10 can recognizethe same. That is, an alarm can be issued to the occupant 10 by means ofthe seatbelt 14.

Further, since, in the warning operation, the drive time of turning ofthe electric motor 29 for tightening the seatbelt 14 is set to be longerthan the drive time of reversing to loosen the seatbelt 14 immediatelyafter that, the amount of releasing the tightening after the seatbelt 14is tightened can be reduced. As a result, the occupant 10 is caused tobodily sense repetition of drive in the tightening direction of theseatbelt 14 and drive in the releasing direction thereof without feelingany incongruity. That is, it is possible to issue an alarm to theoccupant 10 without the driver sensing any incongruity.

Further, since the electrical seatbelt control unit 35 carries out awarning operation on the basis of a mobile object signal of the radarcontrol unit 39 for predicting a possibility of a contact of thevehicle, an alarm can be issued to the occupant 10 if a possibility of acontact of the vehicle is predicted. Accordingly, it is possible toeffectively issue an alarm to the occupant 10.

In addition, since the electric seatbelt control unit 35 carries out atightening operation of the seatbelt 14 by turning the electric motor 29after a warning operation is executed, the occupant 10 is caused torecognize a possibility of a contact of the vehicle at an earlier stagethan an operation for tightening the seatbelt 14 which is carried outwhen the possibility of a contact of the vehicle is increased, and theoccupant 10 is caused to carry out a contact avoiding operation.Therefore, it is possible to effectively issue an alarm to the occupant10.

Also, in the above description, a description is given, as an example,of the case in which both the explosive type first pretensioner 28 andthe second pretensioner 30 using the electric motor 29 are disposed atthe retractor 20 side. However, the explosive type first pretensioner 28may be provided at the retractor 20 side, and the second pretensioner 30may be provided at the buckle 26 side. In this case, the secondpretensioner 30 restrains the seatbelt by retracting the buckle 26 bymeans of the electric motor 29. Further, the relationship between thefirst pretensioner 28 and the second pretensioner 30 may be inverted.

Also, the seatbelt device 15 may be provided for the driver as a matterof course and may be provided for seats of passengers other than thedriver.

In addition, it is possible that an electric motor 29 exclusively forturning is employed. In this case, the electric seatbelt control unit 35carries out control of the electric motor 29 and control for connectionand disconnection of mechanical engagement between the reel 31, whichwinds the seatbelt 14, and the electric motor 29, whereby theabove-described operation is carried out by alternately repeatingtightening of the seatbelt 14 and releasing thereof.

INDUSTRIAL APPLICABILITY

The present invention relates to a travel safety device for a vehicle,which increases safety in traveling.

According to the invention, when the correlation calculating unitcalculates a correlation involving the distance between the vehicle andan object existing in the traveling direction thereof based on adetection result of an object detecting unit, the safety deviceoperation control unit determines a possibility of a contact between thevehicle and the object based thereon. If there is a possibility of acontact, the safety device operation control unit automaticallydecelerates the vehicle by an automatic brake unit which is a safetydevice secured in the vehicle, and at the same time, carries outtightening of the seatbelt and releasing thereof by the seatbelt devicein line therewith. A occupant is caused to bodily sense a degree ofdeceleration by the deceleration brought about by such an automaticbrake unit, and the occupant is caused to bodily sense shaking broughtabout by the seatbelt through tightening of the seatbelt and releasingthereof by the seatbelt device in line therewith. That is, an alarm isissued to the occupant. Therefore, the occupant can be urged to carryout a contact avoiding operation by suitably issuing an alarm.

1. A travel safety device for a vehicle comprising: an object detectingunit which detects an object existing in a traveling direction of thevehicle; a correlation calculating unit which calculates a correlationinvolving a distance between the vehicle and the object on the basis ofa detection result of the object detecting unit; a safety unit includingan automatic brake unit which automatically decelerates the vehicle anda seatbelt device which automatically tightens the seatbelt and releasesthe tightening thereof; and a safety device operation control unit whichdetermines a possibility of a contact between the vehicle and the objecton the basis of the correlation calculated by the correlationcalculating unit and for controlling operation of the safety device whenit is predicted that there is a possibility of a contact wherein thesafety device operation control unit simultaneously actuates theautomatic brake unit and seatbelt device when it is predicted that thereis a possibility of a contact.
 2. The travel safety device for a vehicleaccording to claim 1, wherein the automatic brake unit is constructed soas to be capable of decelerating the vehicle in a plurality of differentdeceleration patterns, and the seatbelt device is constructed so as tobe capable of tightening the seatbelt and releasing the tighteningthereof in a plurality of different operation patterns.
 3. The travelsafety device for a vehicle according to claim 1, wherein the safetydevice operation control unit is constructed so that, when the distancebetween the vehicle and the object enters a predetermined range on thebasis of the correlation calculated by the correlation calculating unit,the automatic brake unit causes deceleration of a degree, which iscapable of making the occupant recognize that a braking force has beengenerated, to be generated, and at the same time, the seatbelt devicealternates tightening of the seatbelt and releasing thereof.
 4. Thetravel safety device for a vehicle according to claim 3, wherein thesafety device operation control unit is constructed so that a furtherhigher degree of deceleration is generated by the automatic brake unitif such a state is maintained for a predetermined period of time, wherethe distance between the vehicle and the object enters a predeterminedrange on the basis of the correlation calculated by the correlationcalculating unit.
 5. The travel safety device for a vehicle according toclaim 4, wherein the safety device operation control unit is constructedso that, if such a state is maintained for a predetermined period oftime, where the distance between the vehicle and the object enters apredetermined range on the basis of the correlation calculated by thecorrelation calculating unit, the seatbelt device causes the seatbelt tobe fixed in its stopped state for at least a predetermined period oftime after the seatbelt is tightened.
 6. The travel safety device for avehicle according to claim 5, comprising: a braking operation detectingunit which detects a braking operation carried out by a driver; and avehicle speed detecting unit which detects the speed of vehicle, whereinthe safety device operation control unit is constructed so that fixingof the seatbelt in its stopped state by the seatbelt device is releasedin at least one of the states where it is detected on the basis of adetection result of the braking operation detecting unit that a brakingoperation is released after the braking operation is carried out by adriver and where it is detected on the basis of a detection result ofthe vehicle speed detecting unit that the vehicle stops.
 7. The travelsafety device for a vehicle according to claim 1, comprising a brakingoperation detecting unit which detects a braking operation carried outby a driver, wherein the safety device operation control unit isconstructed so that, on the basis of a braking operation detected by thebraking operation detecting unit, it determines whether there is apossibility of a contact between the vehicle and the object, andincreases a tightening tension of the seatbelt by the seatbelt device ina case in which it is predicted based on a braking operation carried outby a driver that there is a possibility of a contact prior to a case inwhich it is predicted, on the basis of the correlation between thevehicle and the object, which is calculated by the correlationcalculating unit, that there is a possibility of a contact therebetween.8. The travel safety device for a vehicle according to claim 1,comprising an in-vehicle LAN, wherein the correlation calculating unit,a brake control unit which controls the automatic brake unit and anelectric seatbelt control unit which controls the seatbelt device areconnected to a connection bus of the in-vehicle LAN.
 9. The travelsafety device for a vehicle according to claim 1, wherein the operationof the seatbelt device is made different in a case in which there is apossibility of a contact with a stationary object and in a case in whichthere is a possibility of a contact with a mobile object.
 10. The travelsafety device for a vehicle according to claim 1, further comprising acollision sensor which detects a collision of a vehicle, wherein thesafety device is further provided with airbag devices, wherein thesafety device operation control unit is constructed so that itsimultaneously actuates the automatic brake unit and the seatbelt devicewhen it is predicted that there is a possibility of a contact, andactuates the airbag devices when the collision sensor detects collisionof the vehicle.
 11. A seatbelt device comprising: a seatbelt whichrestrains an occupant of a vehicle in a seat; a contact predicting unitwhich predicts a possibility of a contact between the vehicle and anobject; an electric motor which tightens the seatbelt when a contact ispredicted by the contact predicting unit; a tightening releasing unitwhich releases the tightening of the seatbelt; and a control unit whichcontrols the electric motor and the tightening releasing unit; whereinthe control unit carries out a warning operation to issue an alarm tothe occupant by means of the seatbelt by controlling the electric motorand the tightening releasing unit so that tightening of the seatbelt andreleasing thereof are alternated.
 12. The seatbelt device according toclaim 11, wherein a time of tightening the seatbelt in the warningoperation is set to be longer than a time of releasing the tighteningthereof.
 13. The seatbelt device according to claim 11, wherein thecontrol unit carries out the warning operation on the basis of aprediction signal of the contact predicting unit.
 14. The seatbeltdevice according to claim 11, wherein the control unit carries out atightening operation of tightening the seatbelt by means of the electricmotor after the warning operation is carried out.